2

Here is my code so far:

import arcpy
from arcpy.sa import *

arcpy.CheckOutExtension("Spatial")


workspace = arcpy.env.workspace = "C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6"
arcpy.CreateFolder_management(workspace, "NDVI")
arcpy.env.overwriteOutput = True


RED_1 = arcpy.Raster("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/landtm1.img/Layer_3")
NIR_1 = arcpy.Raster("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/landtm1.img/Layer_4")

RED_2 = arcpy.Raster("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/landtm2.img/Layer_3")
NIR_2 = arcpy.Raster("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/landtm2.img/Layer_4")

RED_3 = arcpy.Raster("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/landtm3.img/Layer_3")
NIR_3 = arcpy.Raster("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/landtm3.img/Layer_4")

print "Program recognizes raster bands."

NDVI_1 = (NIR_1 - RED_1)/(NIR_1 + RED_1)

sr = arcpy.sa.Con(RED_1<>0, NDVI_1, -9999)

NDVI_2 = (NIR_2 - RED_2)/(NIR_2 + RED_2)

sr = arcpy.sa.Con(RED_2<>0, NDVI_2, -9999)

NDVI_3 = (NIR_3 - RED_3)/(NIR_3 + RED_3)

sr = arcpy.sa.Con(RED_3<>0, NDVI_3, -9999)


print "NDVIs passed"


arcpy.CopyRaster_management("NDVI_1", "C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/NDVI", 
format= "TIFF")

When I run the code I get these two errors: ExecuteError: Failed to execute. Parameters are not valid. ERROR 000732: Input Raster: Dataset NDVI_1 does not exist or is not supported

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  • 1
    What happened when you run the code?
    – ahmadhanb
    Dec 8, 2017 at 5:04
  • sr is being overwritten twice, do you want the 3 X sr to be the 3 bands of a raster? If so make the variables sr1, sr2 and sr3 then use CompositeBands_management([sr1,sr2,sr3], "C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/NDVI/NDVI_1.tif") resources.arcgis.com/en/help/main/10.2/index.html#//… - Arc is smart enough to understand you want to export to GeoTIFF format if you supply the file extension. Also I believe that Not Equals is != in Con resources.arcgis.com/en/help/main/10.2/index.html#//… and -9999 isn't a good value to use. Dec 8, 2017 at 5:09
  • 1
    It will promote the pixels from 8 bit unsigned to 32 bit signed integer type.. which will cause havoc in trying to use the data in a 3 band image. I can see the code but as @ahmadhanb is alluding, what is the actual problem you're having? Dec 8, 2017 at 5:13
  • When I run the code I get these two errors: ExecuteError: Failed to execute. Parameters are not valid. ERROR 000732: Input Raster: Dataset NDVI_1 does not exist or is not supported
    – K.J
    Dec 8, 2017 at 5:15

1 Answer 1

3

This should be the correct syntax:

NDVI_1.save("C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6/NDVI.tif")
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  • That is true for a single band but we're not really sure what the actual problem is. Still, you are correct so +1 from me. Dec 8, 2017 at 5:15
  • 1
    Yes, the code is a bit vague so I just went with the simple answer.
    – Dan
    Dec 8, 2017 at 5:17
  • Oh sweet. It works! Yeah I'm extremely new to arcpy and python in general so my code is still clunky, but it's getting there. Thanks Dan.
    – K.J
    Dec 8, 2017 at 5:19
  • Looking at your band syntax, it doesn't look quite right K.J. Are you sure the bands are called 'Layer_'? If you browse to the rasters in ArcCatalog in contents view are the bands called Layer_1, Layer_2 etc or is it Band_1, Band_2 etc..? Dec 8, 2017 at 5:27
  • It's Layer_n with n ranging from 1 to 7. It comes from landsat TM data
    – K.J
    Dec 8, 2017 at 5:42

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